Most epidemiological research on infant feeding has been static in conceptualization, focused narrowly on analysis of the extent and duration of breast-feeding, and provided little insight into either the dynamics of changes in infant feeding patterns or their determinants. This study utilizes a unique longitudinal data set to address pressing questions about feeding patterns and determinants. The first task will be to describe the full pattern of infant feeding, including prelacteal feeding and water use. Clustering techniques will be used to construct logical food categories to be used in realisticaly describing the changing character of the milk and supplemental food components of infant diets over the first two years. Two-year feeding profiles will be developed for each child. The second task will be dynamic analysis of feeding pattern changes and the factors associated with these changes over time. A full set of bomedical, socioeconomic, and community factors will be used to explain the choice of feeding patterns. Estimation techniques will be used which make full use of the longitudinal nature of the data set. This project analyzes data collected from a randomly selected sample of 3,100 Filipino mother-infant pairs who are followed from the mothers' pregnancies through the first two years of the infants' lives. Collected under separate funding, these data come from a survey specifically designed for this and several related analysis projects. The data set includes complete dietary information as well as a huge time-specific compilation of biomedical, demographic and socioeconomic information. A multidisciplinary group (anthropology, economics, nutrition, pediatrics and statistics), which has worked together for several years on related topics, and which designed this survey, will carry out the analysis.